The present invention relates to a fuse circuit for use on an integrated circuit chip to connect or disconnect circuit elements.
The traditional method of connecting or disconnecting circuit elements on an integrated circuit chip has been to use actual fuses such as polysilicon links blown by electrical current or laser blown links. Polysilicon links have the disadvantage of requiring removal of the protective coating on the chip over the fusable link before a reliable open-circuit fuse blow can be obtained. Laser blowing requires elaborate equipment and controls, and must be done before protecting coating is applied. Both of the foregoing processes result in the generation of slag left over from the melting process. U.S. Pat. No. 4,562,639 issued to McElroy Jan. 7, 1986 and assigned to Texas Instruments describes a thin-oxide fuse element which is programmed at a voltage below the oxide breakdown level so that small holes or perforations generated in the oxide are filled with silicon and become short circuits.
Accordingly, it is an object of the present invention to provide a fuse circuit for connecting, disconnecting or otherwise altering circuit elements on a semiconductor integrated circuit chip. It is a further object to provide a fuse which is simple and inexpensive to program, is highly reliable, and does not require any standby current.